Hi there. Hate to ask, but is that fluffy bedding in her nest? It is very dangerous stuff - it can wrap around legs leading to amputations and wrap around teeth, impact pouches and cause digestive blockages leading to death.
If it is, then remove it asap! The safest nesting material is plain white toilet paper - tear the individual sheets into strips and put a big pile of it somewhere in her cage. She will pouch some and take it somewhere to build a nest.
As for her moving her nest - this might be if you had just cleaned out the house - they don't like their scent being taken away and get anxious about things like that. Or maybe she just wanted to build a bigger nest than the house would allow for.
It looks like a nice burrow she has dug there in that corner! Which sounds like she no longer likes the house for some reason! What kind of hamster is she? Also just wondering if her cage is big enough. They need a good sized cage for plenty of enrichment
Apologies if it is, I can't tell from the photo.