1. What does it mean?
점메추 takes the first syllables of 점심 메뉴 추천, lunch menu recommendation. In a chat, 점메추 좀 means 'Give me a lunch idea.' A reply can use it to introduce a suggestion too.
Also written or said as jeommechu
2. The nuance
It is casual shorthand, not a particular dish. The recommendation may be a meal to cook, a restaurant choice, or a delivery option.
3. Examples
“매일 같은 것만 먹어서 점메추 좀 부탁해.”
I keep eating the same thing, so please suggest something for lunch.
“오늘 점메추는 따뜻한 국수야.”
My lunch suggestion today is a warm bowl of noodles.
Sources
Sinjoeo Korean Slang Dictionary
References support the meaning and usage. Example sentences are written for NoCapWiki.