I have an idea for a campaign that is themed after the Spanish colonization, with its primary settlement being something similar to Mexico. I know that I want mexican culture as well as native tribes of the "New World" to play a part in the world but I can't seem to connect the dots. Also, I plan for something similar to the Spanish Inquisition to happen throughout the spanish colonies, torturing heretics while also converting natives to their religion. Its a work in progress I know, but any advice or suggestions would be greatly appreciated.

You should look for the Maztica campaign setitng for inspiration on this theme, it's "loosely" based upon the ancient Aztec and Mayan civilizations when a New World is discovered by the people of Faerun and start to sail there to explore and colonize it, endorsed by the deity Helm.

This can be the basis of a great campaign. I'd be extra careful to talk to the players about the colonization theme. The historical record you are referencing isn't always nice and is, quite often, pretty brutal and sad. I'd do a session zero check on how much the players can/want to delve into that.

I have run settings with colonization themes and had it go well - because we talked about it before we just went at things.

Have to agree with the advice on themes of colonisation, racism, and torture- discuss with the players before the game. As well as this, I would recommend watching Matthew Collville’s video series on political campaigns- they are unbelievably useful for running games with  reaching conflict and different cultures. 
Apart from that, have fun, and I hope the game goes well!

I agree it's definitely something that should be carefully handled and integrated in any game's Safety Tools to respect everyone's limits.

The PDF of Maztica Campaign Set on DMsGuild ended up getting a warning, WoTC added a sensitivity disclaimer stating:

We (Wizards) recognize that some of the legacy content available on this website does not reflect the values of the Dungeons & Dragons franchise today. Some older content may reflect ethnic, racial, and gender prejudice that were commonplace in American society at that time. These depictions were wrong then and are wrong today. This content is presented as it was originally created, because to do otherwise would be the same as claiming these prejudices never existed. Dungeons & Dragons teaches that diversity is a strength, and we strive to make our D&D products as welcoming and inclusive as possible. This part of our work will never end.

Thanks for your recommendations and I definitely agree with talking to my players beforehand. Appreciated.