Please let me know what it is.

more chunks = more space for a land

chunks are rewarded when u complete certain milestones in mcstats, like increasing ur lvl in swords, miner, etc

i have so many chunks that i cant use all of them

thank you very much

Do the chunks unlock by themselves or do you go to /land

They unlock by themselves, but you have to claim them yourself.

Ok thank you very much

What is the command to claim those earned chunks?