Hello OP,
I would just say don't worry. I totally failed to prepare DD for nursery FT at 6 months - she wouldn't drink milk/formula/water anything from a bottle, only ate mushed solids when she felt like it. For the first two weeks of nursery, she refused everything (while screaming for most of the day) and the patient and excellent staff ended up syringe feeding her water! (Just a little bit of guilt). But she did get the gist because babies do have a survival instinct. I would think a 10 mo can look around and figure out what everyone else is doing, and copy. In our nursery, the 10mo know whose milk beaker is whose... they certainly understand how to use them.
For me, going back to work was a terrifying prospect and I wanted to control each aspect, and plenty of other mums I work with have said they felt the same, so I think it is really very normal to really really worry about how the baby will be and want to control it all. Trouble is with babies is that how much they eat/drink on a given day is really difficult to control (!), and a challenge you are, on balance, not likely to win. Of course, I did not realise this at the time either!
At 10 mo babies can manage a slow flow beaker I think, maybe that would work, but even if not, the nursery are not going to let your DS starve or dehydrate. They will syringe water into him if they really have to, but he is old enough to probably avoid that. One of the Mum's at our nursery went in every lunch time to BF her DS, never an option for me, but if you can, then do it. You are allowed time at work to express, and arguably, actually BF is a form of expressing...!
The other thing is that, assuming your DS is going to nursery, they do at least three meals a day IME, so if you are only giving him two solid meals, maybe upping the number would help. I got it all wrong with DD, she wanted interesting chunky food at nursery, and I was still feeding her bland gloop...once she got it, she was a lot more hungry for solids.
Also, a lot changes in a month with babies, and he may be more in favour of it all in a months time. Maybe try cups of water and play with him, my DD was much more into cups and never really did the bottle thing, although beaker thing did work, but never with milk...
Whatever happens, good luck, it is a difficult time, but it will all work out once you get into the new routine.