I do not have direct experience in this area but others may be able to comment.
Just for a fair warning pairing chinchillas together does not always work. Chinchillas can turn on each other without warning at any time even after they are bonded. Make sure to have a hutch or shelter where one of them can hide in the cage at all times. This minimizes but does not eliminate the risk of them killing each other. Some chinchillas are not compatible with each other.
Older chins that are used to living alone are harder to pair than chins that have been together before. Once chinchillas are bonded there is a slight risk that they will become dependent on one another. Therefore if one dies the other may become depressed and die unless a new cage mate is introduced quickly.
Male chinchillas are easier to introduce than females. It doesn't matter if they are the same color or even from the same litter. Each animal has its own personality and tolerances. Even if they are bonded, if chinchillas are temporarily separated for a couple of weeks, for example, to treat a sickness in a different room, you may have to start the process over.
This is the process I am familiar with. Place the cages next to each other no closer than 2 inches apart. Do this for two weeks. When you clean the cages take a part of the soiled bedding from each others' cages and swap them. This helps them get used to having the smell of the other animal in its territory. After two weeks let them play together or dust bathe together where you can separate them quickly and watch very closely. If it doesn't look like they are going to kill each other put them in one cage. They may mount each other and get vocal at first. If they pull each others' hair out then make sure to separate them again. Hair pulling can be a precursor to fighting. Of course biting or wounding is unacceptable and extremely dangerous.
If after two weeks they are still fighting each other wait another week. If that still doesn't work there are additional methods.