Manahive

Equivalent cards to “Nix” (instant, counter target spell if no mana was spent to cast it, color: blue):

• “Disrupting Shoal”: Counters spells by exiling a blue card and is also blue.
• “Annul”: Counters artifact or enchantment spells, also blue, but a bit narrower.
• “Miscast”: Counters instant or sorcery unless its controller pays 3; blue, targets cheap spells.

Reason: All are blue instants focused on countering spells with specific or cheap costs. None are exact, but these are closest in blue.