Do you have any experience in FamiStudio or FamiTracker?
These two are the main programs you may need to get familiar with if you want to make music for actual NES video games.
The NES has only 5 sound channels, and each channel can only play one note at a time. Though the last sound channel is sampled, so you could sample chords there, but you'll have to use tiny samples to fit inside the compo's 64 kibibyte (think 1024x64 bytes) limit.
Point is, the NES is very limited when it comes to the kind of audio it can do, as well as the processor itself being limited when it comes to what it can push in a game. With only 64 kibibytes, you can't expect to be able to render out a whole streamed audio file and put it in the game like that.
I don't see any chiptune in your portfolio, so it looks like you have something to learn about both the NES and its audio hardware.
From one musician to another, I wish you good luck in following this tutorial: