555 to drive a MOSFET
The 555 output can Source or Sink 200 mA so unless you want to drive the mosfet in high frequencies it will be more than enough. A single transistor is probably going to drive the mosfet worse than the 555 itself



If you are need to use a driver between the mosfet and 555 then you are better off with a push-pull (totem pole) driver configuration that can sink/source current equally strong in order to turn on/off the mosfet quickly (again only if needed)



or even better with a dedicated mosfet driver like  TC4426/27/28