For me, nostalgia comes in a few forms. I lived my childhood in 2 places, within 2 cultures. The whole way through we were quite poor. The first part I lived in Bakersfield California with my mom and grandma. We were average for Anglo-Americans in the region at the time (1989-1996) in terms of culture. Nostalgic foods from then are meatloaf, pickled olives, macaroni and cheese with hotdogs cut up in it, and beanie weanie soup (pork and bean soup with hotdogs in it). If you're noticing a trend, it's because hotdogs are cheap protein. I also regularly ate Cantonese food because my grandpa worked for the owner of the restaurant.
The second part I was in Canal Winchester Ohio from 1997-2007. All around me was different from what I had been accustomed to, and so was my home life. My mom married the son of Mexican immigrants and it was culture shock in the extreme. We actually got poorer during this time, and now I was eating practically no American food other than pizza on Saturdays. But, there was one thing I got a bit addicted to, and it was my stepdad's mom's tortillas. Now that she's not with us any more, I tend to tear up when I eat a fresh tortilla.
Unfortunately, my mom can't cook from scratch to save her soul. The one dish she can actually cook is BBQ Enchiladas, that's like regular chicken enchiladas, but instead of a chile based sauce, it's got a Kansas City style BBQ sauce.