I have a new (1 year old) single lever kitchen faucet that has normal flow when the lever is turned to the cold side but only a small trickle of water come out when turned to the hot side.
I changed the disc with no results.

What brand of faucet?

Doug,
The faucet is an American Standard. I replaced the disc with no results. The faucet is only one year old. I am not sure what else it could be except some debri in the hot water line.
Thanks in advance,
John

Hot water sides get 10x more debris than cold. Check the cartridge again and flush with water backwards. You likely still have debris.

You may have a problem in the supply stop [valve] or the supply tube [connector]. Disconnect it from the faucet and try to open the stop into a pail. Check flow there. Then see if you can blow back on the hot side with the cartridge out and the supply disconnected. If the spout is a pull out type you should find a backflow in 2 locations in the faucet. Also check the diverter if you got one.