It's correct, it's an expression that wants to say: you thought well, you had a good idea etc. "Thinking" here is a noun (gerund) and good is an adjective. Adjective + noun is a correct structure.

Hey Carlos This sentence is correct and it can be used when someone gives a good suggestion. I hope my explanation helped 😊

It’s a compliment meaning that someone has a good idea. eg. It was good thinkingto bring your raincoat on this wet day.

(That is) good thinking. Bravo. Great. Arr, a coffee. A great coffee. Just what I needed. A good question. It seems that simply naming something is grammatically ok, sometimes.

Can you put this expression in a sentence, so that we can answer your question better? thanks!