Actually I've been stating that Mueller's charges will be ~"completely trumped up and based on illegally obtained evidence" but that doesn't mean there won't be a mad rush by many to support them as above reproach. I've also been one of the leading voices suggesting that people should not put their faith in the IG report, since it's coming from the DOJ itself.
Trump is a much better position than Nixon was. First, he's not really guilty of what they're supposed to be investigating him for. Second, he has evidence showing there is likely more crimes committed by the investigators, than by him. Crimes of using government powers against a political opponent, just like Watergate, but in the opposite direction. Third, he has some powerful committees in Congress pointing out the crimes that were performed against him. Fourth, he is seen by his supporters as a transformational figure, and they are emotionally invested in his well being.
A better analogy to Nixon, as far as what they are guilty of, and what is going to happen to them ultimately, is actually probably Comey and Mueller.
Speculation re how the Mueller or the IG investigations will play out is useless. We don’t know. Speculation as to how the vast anti-Trump forces would react to a Sessions or Mueller firing is not useless. They’ve already gone insane over complete nothingburgers. All they’re waiting for is something bigger. If Trump gives it to them it will never end. They’ll hound him out of office.
But Trump is too canny to hand them the weapons they need to take him out. He’ll bide his time for now, and then fire the culprits en masse. Sessions gave him little choice on the timing, but once the coast is clear the chickens will come home to roost.