How is consciousness linked to the brain?
This question is difficult to answer and in the end, we'll just have to accept that we don't really know (at least for now). My own understanding is that what we call our consciousness is an emergent phenomenon, arising from the extraordinarily complex network of billions of neurons interacting with each other within the brain. Perhaps the rest of the cells in the body - everything that is interconnected - should also be included. This would mean that we are, indeed, "a mix of chemicals interacting with each other", but in my opinion, that does not make being any less meaningful.

As a side note, although this seems to imply determinism, the future behaviour of complex systems such as our brain, or better yet, the entire universe, is impossible to predict accurately with any computing device. We, as well as the universe, are the best simulators of ourselves.

I think it is really difficult to handle questions like this. To start with, how do you even define "consciousness"? Also, I don't think that such a discussion belongs to philosophy; surely any plausible explanation of conciousness must be rooted within the framework of science.