Air carrier pilot reported ramp personnel failure to follow procedures resulted in being inches from chocked nose wheel as aircraft was still parking.

Narrative

Parking the aircraft at Gate using the Docking Guidance System (DGS); three wing walkers; wet ramp in moderate rain. Aircraft stopped 2 ft. short of mark; applied power; aircraft momentum stopped 1 ft. short; applied more power; felt aircraft lurch forward with shudder. I immediately reduced power to idle and stepped on brakes. Aircraft stopped with DGS reading 'STOP'. Set parking brake; completed shut down and checklist. Upon exiting the aircraft; the Gate Agent in the jetbridge described events they witnessed; the ramper placed chalks at nose wheel at DGS +1 reading as I was attempting to move the aircraft forward. As more power was applied; the ramper attempted to remove the chalks in the nose gear and was bent over right next to the nose gear. Aircraft moved forward 6 inches pushing the chalks forward with the ramper inches away from the nose gear. The ramper did not follow procedures. No personnel are allowed near the aircraft until engines are shut down and aircraft rotating beacon is shut off. A suggestion is all non-flight personnel need to adhere to ramp policies to avoid injury.