Whilst it is possible, it is not easy. The biggest issue will be opposition from various groups including farmers and locals who are tricked into believing they are dangerous - as I understand jaguars almost never attack people. Of course, almost never doesn't help if you are the one.
However, jaguars do not like to be close to humans. As such, there are few areas of contiguous habitat suitable for them, as they need reasonable size home ranges, and the ability to mingle to develop into a viable population. Their preferred habitat is dense forest and wetlands - they really like water. Not sure where the best location would be.
As a concept, I think re-wilding is really interesting. Having apex predators in the environment is a net positive and allows a much broader ecosystem to develop. The reintroduction of the beaver in the UK has significantly improved biodiversity in specific areas, but there are still those who wish to persecute them. The same goes with white-tailed eagles. I have been reading for a decade about 'plans' to reintroduce the lynx to Scotland, but I doubt it will happen any time soon.
Whilst it might be possible, I think vested interests will kill any official attempts to reintroduce jaguars.