Well, to start, I think your chinnie should have a little more time to settle in and get more comfortable with you...I think introducing him/her to another chin plus trying to adjust to a new environment may be too stressful. However, to answer your question about introductions...you want to start slow and not rush it, you have to be very patient. This is the way I did my intros: First I put both chins in the same room, in separate cages of course for about 2 weeks to let them get used to the presence of the other chin. Then I moved their cages side-by-side with about 3 inches between the cages (far enough that they can't reach each other to fight). I did this for about a month. At first there was kacking back & forth, biting at the bars and other agressive behavior, then again, I've done intros where the two chins would lay on the side of the cage closest to the other with no aggression, so it can go either way. Then I would switch their cages...put chin A in chin B's cage and chin B in chin A's cage. I would do this a couple of times over a week or two and leave them in the other's cage for a day or two (this is so they get used to each other's scent)
Now, to the BIG part...you'll want to put them together in a small neutral play area (like the bathroom) so if they fight you can quickly break it up. I put NEW chew toys, the dust bath and a couple of cardboard boxes for them to play with...just to keep them busy. I also kept a bath towel on hand so that if they started to fight I could throw it over them...for some reason tossing a towel over them makes them stop and stand completely still...did for me anyway. Put them together and see how they do. Expect them to chase each other and try humping each other...they are just trying to establish dominance. They may also kack at each other. Mine would stand up on their back legs and kack at the other. If there is ANY aggression, break them up and separate them...wait a week or two and try again. You'll only want to put them together for about 15 minutes or so. If the first attempt is successful, do it again. I let mine play each day for 15 minutes, then gradually increased the time they were together, supervising the whole time. After about 2 weeks of successful playtimes I put them in the same cage together for a few hours each day for about a week. It's best to thoroughly clean whatever cage they will live in together and rearrange shelves, hidey houses, etc...this makes it a neutral home for them.
If there is any aggression during introduction you can trim their whiskers, put a small dab of vanilla just above their noses, give them a dust bath BEFORE putting them together. There is also another introduction method called the SMOOSH METHOD. It is where you put both chins in a VERY small cage, small enough that they cannot move around. Some people take them for a car ride while doing this. It not only distracts them, but allows them to comfort each other on the ride. I've heard alot of success stories in using this method, but it did not work for me.
You have to understand that not all chins will get along. Some chins are better off living alone, some can play together but not live together. If the first intro doesn't work give them some time and try again, but you definitely don't want to rush it. I hope this helps and please ask if you have any more questions...GOOD LUCK :thumbsup: