First off, Hi and Welcome to HC!
Poor little Nut he sounds like he has gone through an awful time
I'll bet hes really glad hes got such a wonderful home now (even if he doesnt show it
). Since nut is new to your home it is not uncommon for him to be very nervous of the new smells and sounds and other factors of his behaviour may depend on his species. Do you know exactly what species of dwarf Nut is? If not do you have a photo of him and of Bolt? Knowing the species will really help the forum to guide you.
As for the actual taming if you give Nut a few days to settle in before handling him it can make things a lot easier. Then you can start introducing your hand with treats on it and just leaving it in the cage for as long as possible even if he doesnt come near it. Eventually, (and this is the part that can depend on the species) he will begin to realise that you are friendly and start to sniff you or even if you are very lucky climb onto your hand.
It can be a long process but there are lots and lots of threads on here that will guide you through the process of getting Nut used to you. Just neve give up on it!
As for Bolt he sounds like a lovely hamster but you may not want to keep the two together with Nut being so nervous and them being from different litters. It may cause fighting between them and it may make taming Nut harder but there are plenty of dwarf hamsters that live alone very happily so no need to frett over that.
Nut and Bolt are very lucky to have you as an owner and I bet in time Nut will become an amazing friend to you.