Not so sure myself, her power is kind of vague in terms of range, and even small nukes (red mushroom bombs really heavily implies nuclear equivalent devices) have quite large ranges. Unless her powers have reached past even the most distant suburbs of Haven I think the nukes might still be able to hit some people with lethal effects that aren't in range for Chernyl's nightmares yet.
Not quite that long range.
And something with wings can cover a couple km in a few minuttes.
We lack a guarantee that nightmares cant move outside their spawning zone.
They were real enough they could not be time frozen.