As much as I love that performance, her vocals were melodyne'd in a few spots.
If it had been, I think that would be very controversial for many fans - and I think they would have commented on it at the time, if it had been an issue then.
However, Melodyne can be difficult to detect - in studio contexts, it's probably the best software available, and it won a technical Grammy for best contribution to recording technology (I think around 2012). Software enhancement can be used to work on single notes, not just wave forms, in principle, to modify what the mike picks up, before the audience even hears it. It's important to bear in mind that, if software had been used, it would presumably have been the broadcaster's decision, not Carrie's - and she may not have been aware of it.
I can't watch the video in question, as the media company have not made it available for my country. From memory, I wasn't a huge fan of the medley at the time, though, as it didn't really come across to me as being as "organic" as some of Carrie's other performances. It's rather difficult to explain what I mean by "organic" - and it is a subjective impression - but, for me, it's to do with harmonizing with the music, having a sense of immediacy, and naturalness in the delivery - Carrie often achieves this better, in my opinion, and, for me, that medley seemed rather over-staged, and too dependent on particular bouts of vocal bravura to be wholly satisfying.
But comparing another performance of "Blown Away" at the CMAs with Carrie's earlier performance of "How Great Thou Art" at an ACM event, I did notice that there were more pitch variations in the long sustained notes of the latter song. This may be influenced by the fact that Carrie was younger, the song was more spiritual, and the delivery was more closely intertwined with the music - but, at least for me, it was a more satisfying rendition. Obtaining the impression of an even pitch in a long sustained note is one of the main uses of Melodyne, and other audio software - but this poster seems to be saying that Melodyne itself is not suitable for live performance, and other software may have to be used instead.
https://www.gearslutz.com/board/music-computers/809175-best-pitch-correction-live-performance.html
If broadcasters of live performances don't use any software enhancement, problems can sometimes arise. For example, EOTY Garth Brooks admitted miming to a recording (which may have been already modified in the studio - making the concept of a live performance problematic). Artist of the Decade, Jason Aldean, unfortunately, has become rather noted for having difficulty in staying in tune in his live duets, whether through nerves or whatever - Kelly blithely sings over him, Miranda pretends he's not there - sometimes you'd almost want some software to come to the rescue!
Even though I'm no expert in the field, and would always generally give mood, expression and sincerity priority over technical perfection (one reason I usually prefer the Opry to the networked spectaculars) - I think Carrie would be about the last person to need this sort of engineering wizardry in any of her showcase performances.