Like all of the Straw Hats, Nami has changed in many ways through her years in One Piece. Even if there hadn't been a two year timeskip, her and the Straw Hats have been through enough adventures to change anyone's outlook on the world.
However, some things need to stay the same otherwise the end result will be a completely different character. Some change is good, but too much can jeopardize the integrity of the character and cause fans to stop enjoying them. Nami was one of the first Straw Hats to join up, so she's had plenty of time to adapt and change while still holding on to what makes her special.
10 Has Changed: Combat Ability
Nami started the series as an absolute weakling when it came to fighting. She needed to be protected from harm by the rest of her crew, and typically tried to run away if any fights broke out. It wasn't until Usopp made her a weapon that utilized her knowledge of the weather that she was finally able to start holding her own on the battlefield. Now she can call down lightning and has proved instrumental in several of the Straw Hats victories.
9 Still The Same: Expert Navigator
Even from a young age Nami was gifted with maps and charting courses. It's the whole reason she was forced to join the Arlong Pirates, and now the role she fulfills with the Straw Hats. Without her navigation skills, the Straw Hats wouldn't have come as far as they have and attaining the One Piece would just remain a dream instead of a reality. Being one of her core skills, there's really no way that she could change and give up on maps and navigation.
8 Has Changed: Loyalty
When Nami was first introduced in One Piece, she appeared to be nothing more than a selfish thief. She only stuck with Luffy for awhile because it was beneficial for her, and left immediately after to return to Arlong.
This wasn't out of any love for Arlong, but as an attempt to protect the people of the island. While originally she didn't care about anyone outside of the islanders, she gradually accepted the Straw Hats into her inner circle and now sees them as family.
7 Still The Same: Love For Money
Nami's love for money is surprisingly unselfish. She originally sought out as much wealth as possible because she was trying to buy her island back from Arlong to save the islanders. Even after Arlong was defeated, she already formed a drive to gather money. She is in charge of spending for the Straw Hats, and now does her best to make sure they are well funded. She still gets excited when the mention of treasure or riches pops up and won't hesitate to go after it.
6 Has Changed: Confidence
Nami isn't a coward, but for a long time she would shrink back at any mention of danger. She was part of the cowardly trio with Usopp and Chopper, but that gradually changed throughout the series. She began growing more confident in her abilities, and now leaps into situations that she would've fled from before. Part of this is due to her combat abilities growing through the years, but another part of it is her bond deepening with her fellow Straw Hats. It's only natural now for her to want to keep them safe.
5 Still The Same: Scary
While she appears to be sweet and charming, Nami also has a bit of a malicious streak. It doesn't appear often, but if she gains control over an enemy this dark side may come out. This came out several times in the Whole Cake Island arc when she gained power over others, like when using the vivre card against the homies or when she admonished Zeus for turning on her. She's done this several times throughout the series, and it doesn't seem like she will be stopping soon.
4 Has Changed: Physical Appearance
It's been about two and a half years in the show since Nami was introduced. Her physical appearance changed quite a bit, especially after the two year timeskip. She finally grew her hair out, so now it flows down her back instead of stopping at her shoulders.
Her fashion sense has also changed, as she continues to try out various different looks.
3 Still The Same: A Hidden Strength
While Nami appears to be physically weak compared to most of the crew, that doesn't stop her from beating them down if they make her mad. On many occasions through the series she's punched members of the crew, particularly Luffy, hard enough to leave large welts and bruises. While this seems to be more for humor than any actual display of strength, it's still been something she's been able to do since the very beginning of the series.
2 Has Changed: Opinion Of Pirates
Nami had an understandable hatred of pirates when she was first introduced. She could attribute all of the hardships she had to endure to the Arlong pirates, and took great pleasure in stealing treasure and gold from other pirate groups. This finally changed when she met Luffy and realized that not all pirates are like those she knows. While she still believes most pirates are bad, she has come to make certain exceptions like with Trafalgar Law and his Heart Pirates as well as the rest of the Straw Hats.
1 Still The Same: Tributes To Her Past
Nami has a deep and long lasting connection with her past before joining the Straw Hats. She didn't completely let go of those she left behind, and she made sure she had some reminders of them for her journey. Her tattoo is a tribute to some of the islanders she was closest to, and a good replacement for the previous Arlong tattoo. She also made sure there were tangerine trees planted on the Going Merry and Thousand Sunny as a tribute to her late adoptive mother Bellemere. While she accepts that her life has her moving forward, she's never been afraid to look back and remember.