It's wild how close this is to true, but by my measurement the shortest distance between the US mainland (so not counting Puerto Rico) and the nearest point I can see in the Amazon [white outline in 0, for lack of a better reference] is ~1,650 miles, and there is nowhere in Brazil that is more than 1600 miles.
The northernmost part of Brazil is closer to Canada than it is to the southernmost part of Brazil. So yes, there are places on the US that are closer to the Amazon than some places in Brazil
[0]https://en.wikipedia.org/wiki/Amazon_rainforest#/media/File:...