>If free will exists, that would seem to imply that people can make decisions that affect their future. Wouldn't free will therefore imply nondeterminism?

Not necessarily.

"Free will" is being able to express your actual self (your will) in a decision.

But if on a matter that calls for A or B decision, you can make either A or B, then "you" are not a coherent thing (because you can go multiple ways. Wouldn't a person that is authentically themselves can only chose one option --the one truer to themselves and their ideas, courage, cowardice, etc.-- each time?).

So, what if there's only one possible outcome of each decision one makes each time, and the set of prior decisions (that they followed A in this matter, B in the other, and on on) is what defines you as you?

Then free will and determinism are the same thing -- the untangling of yourself as a unique being.