Kind of a vague question, but yes you can put mud tires/other aggressive "off road" tires on your KK. It all comes down to what is made for what size. Any particular tire your looking for specifically? Also what size? Most importantly what size rim do you have?
For the record, Rubicons come with BFG Mud Terrains.
2011 KK - Skyslider - JBA Adjust-A-Strut - OME 731 - Bilstein Shocks - JBA UCA- 245/75-16 Duratracs