I'm looking for the episode and enemy name from a Batman cartoon from probably the '90s. The enemy is a skinny nerdy character with a cane for a weapon, his glasses have a clock face on them and he knows the speed of Batman's punches and kicks and so can dodge them. He's very fixated on 'time'.
You are definitely looking for The Clock King episode from Batman: The Animated Series.
The enemy is a skinny nerdy character with a cane for a weapon,
Yup. Bonus: it's the hand of a clock.
his glasses have a clock face on them
and he knows the speed of batmans punches and kicks and so can dodge them.
This is accurate. He has studied Batman in-depth and attempts to use the statistics against Batman.
Fugate: I've studied news footage of you, and I know that it takes you exactly a twentieth of a second to throw a punch.
Batman: Very clever. But it only takes me a thirtieth of a second......to do this! (Throws a kick at Fugate)
He's very fixated on 'time'.
Temple Fugate starts out as a nerdy time-obsessed lawyer. When a co-worker suggests he relaxes a bit, he ends up being late for a court appearance, and loses his case and eventually career. He blames his co-worker for his ruin and becomes a criminal bent on revenge.