If you want them to be together, it is very important that one of them is fixed. It's probably a better choice to fix the male because they have a higher survival rate compared to females who are spayed. The process is usually less invasive for males. Be sure you wait over 8 weeks after the operation before you begin introducing the two; if you plan on doing this operation, please do lots of research so that you are prepared for the aftermath. After you are sure the procedure went well and there are no chances of babies, you can begin bonding by putting the cages close so that they can smell each other, but not reach each other. Once they seem comfortable, get them used to each others smell by having them use the same dust bath and switching them into each others cages. After this process, which should take many weeks, you can let them free in a large, chin-proofed room with plenty of hiding places. Be ready to intervene into any fights, and maybe use an oven mit to protect from bites. If they fight, restart from the beginning, but be aware that the chances of them bonding has lowered significantly. Do this for a very short time, and increase their play times if they seem comfortable. When they are very comfortable, put them in a cage of neutral territory (either a completely new cage to both of them, or one of the cages that have been thoroughly cleaned and filled with new toys to eradicate any chinchilla smells). Do this for an extremely short amount of time and stay in the same room, constantly watching for fights. Provide lots of hiding places if they want to avoid each other. Continue slowly increasing the time that they are together until they seem completely comfortable with each other. This entire process should be taken extremely slowly, and there is always a chance that it will not work. Remember, it is perfectly fine to have chinchillas in seperate cages; just having another to chat with can be enjoyable for them!
Hope this helped! Reply for any questions :chin2: