How do I change my Nintendo Network ID?

Actually, I have a lot of questions. See, my previous home was in Mexico and my Nintendo Network ID has that country registered. Now I live in the USA and I want to use dollars to buy cards for the eshop but the eshop only accepts Mexican money and I can't change the region because a message says that my NNID doesn't match with my profile. I have been thinking of removing my NNID but I think that will erase all my purchases and I won't be able to use Pokebank, Pokemon shuffle events, or SSB4 online or any other software that requires NNid. I plan to buy Lucas (the DLC for SSB4) but how do I do that if my I can only use dollars and my 3Ds wants Pesos? How do I erase or change my NNiD without these problems? Is there any way of changing region in the NNid?

Sorry for any errors, English isn't my first language.

According to the official help page from Nintendo, you can't change the information that you want to change (your country information).

The Nintendo Network ID (username) and country cannot be changed once the account is created. The only way to change this information is to create a new Nintendo Network ID.

You do not need to delete the current Nintendo Network ID to create a new one on your system. Deleting a Nintendo Network ID will also delete any purchases or digital content that is associated to that account.

Nintendo 3DS family systems can only support one Nintendo Network ID at a time. However, you can format the system to deactivate the current NNID and create a new one. (The existing account and purchases will not be deleted, and can still be re-linked to the same system in the future.)

The only things that you can change without making another NNID are gender, region, time zone, and e-mail address. The country and birthday aren't able to be changed.