if all lands are taped can u use chimeric idol

[stu5545]

can you use chimeric idol when all lands are tapped already?

[Arix]

Yes.

[Swamp]

Can u explain

[Kenji]

What is there to explain? The rulings for Chimeric Idol are pretty helpful as well:

Your lands are tapped as part of the effect, not part of the cost.

It doesn't target anything, nor is tapping lands a cost at all. So, if you activate Chimeric Idol's ability with all your lands tapped, when the ability resolves it'll do as much as it can. Which in this case means that Chimeric Idol becomes a 3/3 Turtle artifact creature until the end of turn.