Nest thermostat to Kelvinator furnace
Simply land your blue wire on the C terminal

Most HVAC control board low voltage terminal blocks are designed to terminate 2 wires under each terminal, as was done with the Y terminal on your control board.  So, turn off the furnace, loosen the screw on the C terminal, land the blue wire there (after stripping the end back if need be), tighten the screw back down, turn the furnace back on, and you'll be good to go.