Tishana's Tidebinder targets the triggered ability on the stack (such as a chapter ability from a saga like Bahamut), not the permanent itself. Because that ability belongs to a creature, the permanent then loses all its abilities as a consequence of the ability being countered.
Tishana's Tidebinder targets the triggered ability on the stack (such as a chapter ability from a saga like Bahamut), not the permanent itself. Because that ability belongs to a creature, the permanent then loses all its abilities as a consequence of the ability being countered.