Hey, I also am interested in potentially working in a Spanish speaking country or in Latin America in general.
Can you give me a better idea of your interests? Are you currently in school? What experience do you have?
Having a small connection in Mexico is a great thing to have, and it's close to the USA which is good for you. Mexico has a lot of opportunities in many fields, especially in Mexico city, many STEM opportunities, but I'm not sure what else. If you decide upon a country you are most interested in, you could go to that country's subreddit and ask people who actually live there for advice.
Chile is a very stable, organized country, but it's far away from the USA. They have a large copper mining sector (Biggest in the world) and I'm pretty sure there are lots of opportunities for foreigners there, but you would need education in Mining or Engineering or Science, or something related.
Colombia is an amazing country and I wish there were more opportunities there, but I think it's more difficult to get a good job there, but you might still be able to get one. Being a native English speaker is a huge asset to large companies there, but isn't enough on it's own, you need more skills to go with it.
Don't forget Peru, their economy is growing faster than most countries in Latin America and there are good jobs to be had, also in mining like Chile, but other types available too.
Honestly, I wouldn't reccomend living/working in Central America, Bolivia, Uruguay, it would be very difficult to get a good job, unless you don't mind living on a very low salary there.
Argentina and Uruguay are great places as well. Many of these countries have lots to offer in their largest cities like BA, Montevideo because there are so many people there. I would think if you spoke Spanish very well and had a good business background, this would open doors in many areas down there. Also, STEM fields tend to be very valuable all over the world and it's difficult to go wrong there.
Hope I helped, anymore questions please ask!