Can i empower a mech token with Sanction

Yes — a Mech token can be Empowered by Sanction.

Sanction's first mode reads "Empower a unit," and token units are units, following all rules for their type (Rule 185.2.d), so nothing excludes them. The only restriction is that you can't Empower something that's already Empowered — if that Mech is already Empowered, that mode does nothing (Rule 441.1.b–c).

Remember Sanction is two-part: the delayed "Disempower it at end of turn" still applies to that token. If the Mech dies or otherwise leaves the board before the Ending Step, the token ceases to exist and the delayed Disempower simply does nothing (Rule 442.1.a.1) — nothing is "stranded" by it.