Many people associate the Millenium with only the period of peace that comes after Christ's return.
However John makes clear in Revelation that the start of the seventh thousand years is not the start of the period of peace, but is closely aligned with it, and this seventh thousand years is also a key millenium which could be termed the Millenium.
Descriptions of a thousand year period with Christ's return at or near the beginning should be distinguished between these two periods.
There is an interesting question here, based on D&C 29:14-21. There, it uses the phrase "before this great day shall come". "This" would seem to refer to the day of the resurrection, and it may be possible from what is written here, that Christ's coming and the day of resurrection described here, will have some space of time between them. Do all of the destructions described here necessarily occur before Christ comes, or might some of the things described here be things that he will do after he comes, but preceding the described resurrection? (ie. Will the wicked all be destroyed at the moment he comes, or before he comes? Before seems implausible given the events which are supposed to be happening leading up to his coming. If not before, then this sort of ultimate cleansing that seems to be described, might come after, and only THEN do we get the period of peace.) Nevertheless there is some similarity between some of the events described here and events that John described in Revelation when the trumpets are sounding, which clearly occur before Christ appears.