Nostalgic
Nostalgia
い adjective
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of nostalgia? It's nostalgic.
The reading is the one you learned with the kanji. Do you remember doing that? Oh man, those were the days. How 懐かしい.
懐かしい！小さいころ、よくやったよね。
How nostalgic! We used to do that a lot when we were kids, didn't we?
この味、なんだか懐かしい感じがする。
This taste feels kind of nostalgic.
懐かしい曲がスピーカーから流れてきました。
A nostalgic song started playing from the speaker.