Student or Learner
Is this sentence correct? :
He's had a chance to change (changing?) his life but he didn't catch it.
You take a chance or act on an opportunity -- don't catch them.
You can say
He HAD a chance but he didn't take it.
This sounds like the chance is in the past and he missed it.
If you use "He HAS HAD" a chance, there is still some applicability to the present.
That man has had a million chances to change his ways and has ignored everyone one of them!
In this case, the present perfect works better for me.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
I would use the simple past, actually.
He had a chance to change his life, but he didn't take it.
This indicates that he no longer has the opportunity. If you want to indicate that the opportunity is still available, use the present perfect in the second part of the sentence:
He's had a chance to change his life, but he hasn't taken it (yet.)