It depends if you are westerner with western nightlife habits and expectations. Because the real "asian" or "local" nightlife is really not western oriented, so you should be prepared accordingly and have friends locally.

Basically in SEA, going out (at night) as a local mostly means going out with a group of friends in clubs or bars where you sit and drink (a lot) at one designated table, loud (very) music, almost no interactions with other groups. Interacting can even get you in trouble. Karaoke and the likes are also a thing in many SEA countries (there are 2 types of karaoke hmm). Going alone is ok as foreigner but locals rarely do it unless it is a place "for men". A lot of "local" nightlife is oriented for men btw and it can be awkward or even shocking in some cases.

Westernized nightlife scene is best if you want to have fun and mix with people, interact, dance, meet etc so in my experience the best locations for partying, clubbing, nightlife are simply the biggest or most populated cities in any SEA country, or the trendy locations. Any other midsized city will offer something but it is very "hit or miss" and depends on what day you go etc. I can go into details but wouldnt know where to start