Actually, you might want to check if there are other flights flying to Tawau after that AirAsia 1220 flight. I think the window you have for the transfer is risky. Consider the possibilities of flight delayed, especially when you fly budget. If you miss your connection, chances are you will have to pay for another flight to Tawau, if there's any. Otherwise, you probably need to stay overnight.
Alternatively, fly AirAsia to KL on the earlier morning flight, if your flight is delayed you still be able to connect. If the flight is on time, then you can have time to enjoy the Old Town Curry Mee at KL Budget Terminal. It's delicious!