Although I haven't course fished a river for many years,( I've just restarted course fishing - commercials at the moment) bread, smelly cheese or bread & smelly cheese paste always used to work for us on Ribble Chub. Mmmmmmm!!
Most baits work if you don't spook them, but when in season freelined slugs are the deadliest bait I have ever found for chub. In fact I'm gonna try freezing some next season and giving them a go in the winter. Last year in autumn I could pop down to the river for a few hours with twenty slugs and catch 10 - 15 chub, with the odd bonus perch.
Two other famous deadly chub baits are wasp grub (or chunks of wasp nest) and crayfish, but native ones are now rare, so are best left alone. Be careful though, only harvest wasps nests if you know what you are doing. Sometimes they are advertised mail order.
Anchored bread crust or flake is also very good. I used to use cheese-paste with good results, but my daughter is too allergic to milk products so I don't anymore.
Wasp grub is one of the best baits for chub,(if you can get your hands on it.)
A good tip for catching smaller chub if theres plenty of other
species in the river such as roach & dace is to feed maggot and fish caster but cast them past the run where the maggots are settling.
Give it a go it works for me every time on the River Tees