Yes, "would have given" is correct. Here is the reasoning:
The use of "could" as in "I could have scored" is conditional, which depends on the hypothetical circumstance -- "if my coach would have given me the chance."
The hypothetical "if" clause implies possibility, but not actual action or fact. It is clear the speaker is talking about the possibility of his winning, had the coach given him a chance to play. But the coach did not give him a chance to play. So the if hypothetical clause, "if my coach "would have given" me the chance" is correct.