With correct technique, the nosewheel will be on the ground when you start feeling the effect of the reversers.
If you try to hold the nosewheel off the ground (which you absolutely should not, even though there are some pilots out there who do it for fun I guess), you will have to add a little back pressure when the reversers come in.
The back pressure is also needed to compensate for the reduced lift of the stabilizer.
Either way, as long as you use correct technique you won't have to worry about any pitch moment caused by reversers.