Your schematic appears to be a buck converter. The supply is bipolar, yet that may be unnecessary.
There are basic buck converters which have a diode where you have M2. Normally the diode points upward. However current will want to flow down from your output stage during the last half of the cycle (I think).
What direction do you expect current to flow when M2 turns on?
I am looking through the menu of LTSpice examples. I do not see a buck converter, nor the IR2110. It might help if you were to find a simple buck converter circuit to start out with.