Buck Converter not increasing the current?
TC4428A is a LOW SIDE driver, that mosfet is not in a low side configuration, what you need is a high side driver and boost capacitor (You have to get the gate up above the supply rail by 10V or so to switch the mosfet on fully).

As it is your gate can only swing up to the supply rail, which will leave the source Vgs below the supply, thus in the linear region and dissipating considerable power.

You also want some input capacitance and some high frequency output capacitance, a few uF or so of MLCC would probably do.