[Nuke]

it appears that its under the dash, left of the steering column

the drawing I ran across looks like its just a bit above the parking brake mechanism to the right. There's multiple cable connectors running to it. Looks like it lies oriented so that you're looking at the flat face of the module.

The lower silencer panel would be removed first and then you can see what components are there.

The TCM (trans) and radio amplifier modules are turned edge-wise and they are oriented towards the driver more (they are also to the left of the steering column.

To the OP: I just happened to be futzing around in this very area of my 2010 Challenger recently and took some pics for reference purposes. Here's one that shows the whole area referenced by @Hal_H and all attached 'modules' (which is only one on mine):

If the BCM is in this location, I'm guessing the red arrow points to it.

I will say that when I installed a Tranzformer on my 2011, I tapped into a module in this same location, though I cannot say for sure if it was that particular module in the pic. If it was, then that would be the TCM I guess. But if that is the TCM, where is the BCM?

Unfortunately I cannot answer any of those questions with any real confidence. But if I had to guess, I'd say that module being pointed at by the red arrow is the BCM, in a 2010 Challenger anyway.