Ajahn Chah seems to place more emphasis on general awareness and so do some of his Western disciples, but this emphasis could of course have been shaped by the talks that were recorded in contrast to those that were not. Or, by the talks I happened to have read.
But I'd say yes to both questions. Ajahn Chah occasionally did refer to nimitta and described deep states of mind; for example here is one talk you can find online: http://www.ajahnchah.org/book/Evening_Sitting.php
. It describes the arising of a nimitta and how meditation goes into a place where the external senses are not active and "all that remains is the knowing". This is exactly how Ajahn Brahm describes the (way into) jhanas. And although in other places Ajahn Chah seems to contradict himself on this, as I've said earlier, we can say at least he referred to these states at times.
Another interesting similarity is they both talk of taking away the 'controlling' or 'willpower' to reach these states. In Ajahn Chah talks I've seen it occasionally, and in Ajahn Brahm says this maybe once every hour.
But in essence it is letting go I mentioned earlier, which Ajahn Chah also used a lot.
Again, I'm very convinced myself, but am not in the best position to convince others.
So apart from the reading I did, I also trust Ajahn Brahm when says Ajahn Chah did teach these jhanas. And also, while they may have a different emphasis, I've never heard or read of any of his other disciples contradict this. As far as I know, people who do try to contradict this (you can find some if you use Google) are people who -like me- only have second hand contact with the teachings of venerable Chah, or perhaps only met him occasionally.