I am looking for daily RN vital collection for my sister-in-law. She is self sufficient and lives alone.

She can order a BP machine from Amazon and take her own vitals.

Why does she need a nurse to visit daily?

Need more info. An RN would be expensive. LPN can pretty much do what an RN can. RN rarely now work with patients, they are more administrative.

A bit more info is really needed.
What "vital collection" is needed?
And if it is just BP, Pulse, and simple info like that much of that can be done by herself if she has the equipment. (not sure if I would trust some of the apps on the phone though)
And is a daily visit necessary?
If this is medically necessary her doctor can order it and it may be covered.
There are companies that do Home Health Visits. Do a search in her area for Home Health Visits and she can call around. (or you can, you do say she is self sufficient though)