Nitpick: We solved nim. We created an algorithm that, when applied, guarantees the first player a win if some conditions are met, and the second player a win otherwise.

There is no equivalent for chess. Instead, we created programs that can apply more general game-theoretic algorithms with ad hoc modifications for chess (for example, minimax with alpha-beta pruning and lookup tables to recognize book openings, closings, and common scenarios) which can, at current CPU speeds and RAM capacities, reliably beat the top-ranked human players.

It is mathematically possible to beat the best computer chess player; it might not, however, be humanly possible. OTOH, it is mathematically impossible to beat a simple nim program which has been programmed with the perfect play algorithm, assuming the game is such that the program will win if it applies that algorithm.

My point is, if something is solved, an adversary throwing more computing power at the process is meaningless. It would merely hasten the inevitable. However, for a problem like chess, an adversary suddenly getting better computers could be a game changer.