Is getting two surgeries done at the same time recommended? I would like to get Orthognacthic and Rhinoplasty surgery done.

getting two procedures done at the same time is fine. Those particular surgeries are not recommended to be done at the same time for two reasons 1) oral surgeons who do orthognathic surgeries are usually not experts at rhinoplasty. 2) orthognathic surgery can have changes on the projection of the nose. so you really want the ortho done first then do the nose after it's all settles. Best wishes

While I frequently do surgeries with my partners at the same time, I would not recommend these two at the same time.  I do only facial plastics and my partners do body contouring plastics and many patients have these at the same time.  This works well because the patients save on OR time and anesthesia, and have only one recovery. 
I do both orthognathic and rhinoplasty surgery, and am probably one of the few surgeons who is craniofacial and facial plastics trained.  I would not recommend pairing these two procedures.  The reason is that most patients need to stay in a splint with their mouth wired shut after jaw surgery.  After rhinoplasty the nose is packed with splints and generally gets blocked with crusts and blood clots.  It is very hard to breathe through the nose after rhinoplasty.  While a patient can breathe through the mouth with jaws wired, it can be very uncomfortable, and it will be worse without nasal breathing.  It's too much at once.  Further, if you are planning upper jaw surgery, the position of the nose can change and this is not a good foundation for a rhinoplasty. 
I would do jaw surgery first, then rhinoplasty 6 months later.
Best of luck
Dr Rodman