As far as I know Biden has not taken any step toward this so far, but many House Democrats are urging him to do so. At the same time though powerful lobbying interests are pushing for the deal to be renegotiated under stricter terms, so I wouldn't count our eggs too early.
More importantly, I would think this is entirely negated by the fact that we just murdered two of their country's most prominent public figures. Diplomatic relations might improve, but I have to imagine that a lot of Iranians would be radicalized by these events and not really care which particular administration is responsible ultimately. Trump might catch the blame, but these type of targeted killings in Iran of scientists and other civilians go back much further than just the last term.