Paying for medical services
ACA sets standards for insurance policies. These include 10 essential benefits that must be included in the policy, no denials of applicants for pre-existing conditions, and no maximum lifetime or annual pay outs. It is this last point that seems most relevant for this question. There can be no limits on how much is paid out in a given year, or over a lifetime, for any medical care associated with those 10 essential benefits. However, there may be other benefits that an insurance policy covers and it is the insurer, not ACA, that could set limits.
So no, there is nothing in ACA that sets limits. If anything, it sets no limits. But mostly, it lets insurance providers offer different policies and once beyond the essential benefits, what those policies include or not is up to the individual insurers.