is congress the appropriate institution to have power over immigration and naturalization? why or why not?

Yes, they are.

Explanation:

Congress is a part of the legislative branch. Which means that they're the one that's responsible in creating laws/regulations.

Policies regarding immigration and naturalization be really depended on the current situation. Having the ability to impose that policies into law in an efficient manner is why congress is the appropriate institution to control them.

For example, during the corona virus pandemic, we need to quickly prevent immigrations from high infection rate into the country. Congress could make a legislation that limit the amount of immigrants that could come into the country.

because mexico wanted to choose a centralized location

here are some major conflicts i found. maybe pick one and do more research on it. (cause i ain't writing 6 paragraphs)

in 1877, the nez perce war took place.

1881 - president james garfield was assassinated.

1882 - the chinese exclusion act was passed.

1883 - a decision in the civil rights cases legalized racial segregation in the united states.

1887 - the dawes act was passed.

1893 - the panic of 1893 took place. (what a creative name)

and there are probably other topics you can find if you just search up "united states timeline," or "conflicts in the 19th century for america."

then once you find a topic you like find out how it affected the people of america and what not. (sorry if this feels a bit short changed, history was and never will be one of my strong topics)