When did chris kyle make chief?

Chris Kyle was never a "Chief." He was a Navy SEAL, and within the SEALs, he reached the rank of Chief Petty Officer (CPO).

It's important to distinguish between the two:

* Chief Petty Officer (CPO): This is a specific enlisted rank in the Navy. It's the highest enlisted rank attainable in the Navy SEALs.

* Chief: This is a more general term, and it's not a specific rank.

Chris Kyle reached the rank of Chief Petty Officer (CPO) in the Navy SEALs.