That depends on the type of picosecond laser treatment and the reason you're undergoing it for.
For pigmentary issues where the laser performed is non-ablative (no burning of the skin layers), it is possible to do the chemical peel during the same session. This is synergistic and will improve outcomes when done together (and properly).
For the management of scars where a focused lens array is used to create ablative potential with picosecond lasers, it might be a good idea to perform the chemical peel 2 to 4 weeks later when the skin has properly healed; the fractional pico sessions can disrupt the skin barrier and result in inconsistent and excessive absorption of the acid which can produce burns.
Do discuss this with your doctor thoroughly to align expectations.