There have been nomadic pastoralists living alongside partially and fully sedentary agriculturalists in Central Asia for thousands of years. The parts of the continent that are inhabited solely by nomads are those areas that are largely unsuitable for sedentary life and were adapted into environments suitable for pastoralists instead.
The idea of nomad communities that subsist solely on raiding poor sedentary farmers is one that gets a lot of play in historical documents (conveniently written almost exclusively by people living in sedentary communities), but it's not a narrative that's well supported as the historical norm by the archaeology in most areas. Instead, much of what we see is produced by complex economic systems involving mutually beneficial trade between these groups. You might have heard these kinds of systems called "silk roads", for example.