As far as I know, there is no motion sensor built specifically for recess lighting. You would need to add a standalone sensor someplace, wired to intercept the power from the switch that controls the recess lighting.
An example of a standalone sensor is shown here, the RAB Stealth: RAB LIGHTING - STEALTH 110 & 200
I will assume there is a wall switch just inside for these lights, the switched power cable rises up the interior of the wall then exits into the ceiling that the recess lights reside.
A sensor could be installed on the exterior of the wall, and wired to intercept the switched power cable.
A wall case box would need to be cut into the wall to contain the splices for the sensor and to support the sensor.
This is a simple job, but for those that know how to trace out wiring, figure out which wire is for what, know how to cut in a box, and wire up the sensor.
For those that do not know all of these details, this can be a nightmare project.
What is your knowledge and capabilities?