Nightbeam Failed against mystical space Typhoon. So its my turn I used nightbeam which is supposed to not allow the opponent to use the targeted spell or trap card. However the opponent responded using the mystical space typhoon that I had targeted to destroy my field spell card in the chain. This clearly should not have been able to occur.

did they chained other card between night beam and the targeted card? because night beam only prevent the targeted card to be activated in response to night beam activation, if there's other card chained to nightbeam the targeted card can be activated normally because its not chaining to night beam