Milling the head has no effect on rocker geometry, as long as you still have an adjustment.
However, any more than a light pass eats the intake valve seat, and when this is re-cut deeper the valve gets taller - this will require a correction.
The easiest is to shorten the intake valves by the same amount as the mill cut, but you may not have enough room before the collar strikes the rocker arm.
Shimming the rocker stands (same amount as the mill cut) has been suggested as a correction, but unfortunately it causes the reverse error on the exhaust valve geometry. This needs either the exhaust valves sunk (not a good idea), taller exhaust valves, or lash caps on the exhausts.
Are you sure the intake valve will not strike the piston?
