Canon 5d mark 3 or nikon d800 for indoor portraits?

Which one to buy for indoor babies' portraits canon 5d mark 3 or nikon d800?

If you love to work with RAW files and ready spent hours in lightroom buy Nikon D800

If you want a noise free JPEG files directly out from your camera buy 5D Mark III

Totally irrelevant.
Get the one you like best. Just be sure you don't empty the coffers so far when you buy the body that you can't afford a good lens and some good lighting equipment.
The quality of the lens, lighting and the photographer have 100x more effect on the quality of the portrait than the camera body.

For the 5D the ultimate portrait lens is the EF 85mm f/1.2 L and/or the EF 50mm f/1.2L.

Photography is roughly 70% photographer skill/experience, 20% lens quality, and 10% camera body. The camera body is only as good as the person using it.

In other words, I would rather have a $600 camera with a $1500 lens than I would an $1800 camera with a $300 lens. Besides, when it comes to doing portraits, the lighting and knowing how to use it properly should also be one of the top priorities.

Both Canon and Nikon make nice cameras. The best thing to do is visit an actual camera shop (not bestbuy/walmart) and try the different models within your budget to see which feels the best to you AND they can answer your questions about the cameras. I bought a Canon for its ergonomics/feel/menu and control layout and a fellow photog chose Nikon for the same reason… It is about personal preference.

Since you have to ask, you aren't experienced enough to justify the purchase of either.

You know that you'll need great lenses for those cameras, right? If you were planning on spending your whole budget on a nice body and then buying cheap glass, that's a terrible idea.

All you need at this point is a Nikon D3200 w/ an 18-55 or a Rebel T4i w/ an 18-55.