It could go top 10 if it was promting a full Christmas album. Otherwise I can't see the label doing promo and radio playing it when it's just one random song for H&M. She's a mess lately.
I'd be happy with a top20 entrance tbh based on how Christmas songs by pop girls perform on the charts...But we still don't know what's the song purpose? Is it only for the H&M campaign? Or it will be sent to the radio, have a music video and 1-2 live performances? Let's see.
If it's a Christmas sounding song like "Santa Tell Me" or "Mistletoe" #21-#40 sounds more reasonable. She should still have a decent boost due to her not releasing for so long though.
If she wants to go higher than that, she needs a combination of the following:
- General song that can be played year-round but also fitting for holidays (i.e. Firework, Party In The U.S.A.)
- Amazing music video released on the same day as the single is sent to iTunes
- Radio deal for first week of release (alongside iTunes release and video)
- Spotify release on same day as iTunes release
- At least two performances in the first week of release, iTunes banner, YouTube/Spotify ads
There's no reason why if it's a great song with strong radio support, sales, streams and promo during its first week, that it can't debut at #1.
and here for the house sound to re-gain UK fans 
The impacT 
