Depends on your price range. Also since it's a .22lr with almost no recoil (plus you're shooting at smaller things a lot of the time) you can take advantage of higher magnification.
Below $1,000: Bushnell MPED 5-30x56, Vortex Strike Eagle 5-25x56, or maybe some flavor of Arken?
Below $2,000: Very uneducated on good NRL22 scopes in this price area but I imagine you could wait until the Zeiss S3 6-36x56 goes on sale again they were selling at $1,875 from October through the end of the year. Heard they're a hell of a lot of scope and extremely hard to beat at that pricepoint.
Above $2,000: Vortex R3 6-36x56, Nightforce 7-35x56, Leica PRS 5-30 (maybe), any flavor of ZCO or TT
The Bushnell/Vortex both have about 30 MIL of internal travel which is a fair bit to work with and they both parallax down to 15 yards. A fair bit above that pricepoint, I just put together an NRL22 build and put a Vortex G3 6-36x56 on it. There seem to be a surprisingly number of dudes using ZCO's on their builds which I greatly envy.