I’ve been really stuck on a lot of the small island nations - St Kitts and Nevis? Palau? With food - I prefer to go to a proper restaurant but for harder cases like Abkhazia I ordered some candy online (and debatable whether that’s a country any way)
I once tried to sleep with the alphabet. Using the first letter of their names. Some letters are just impossible.
Anyway, for Nigeria I recommend Danger by the Lijadu Sisters. It's 70's prog rock by identical twin sisters.
For Canada you should check out Something's Fishy at Camp Wiganishie by Al Simmons, featuring the classic I Collect Rocks.
If you're having trouble finding food from everywhere, damn near every country has at least one special bread, like naan, rye, injera, sopapilla, casava cake etc. If you're into baking you can make the bread.