Hops far more well known for it's effects when drunk has been shown to be a mild sedative even in it's none fermented form. It contains some bitter resins that seem to increase the activity of GABA which in turn plays a part in relaxation and sleep.
There have been quite a few studies into this, although generally they do require a larger amount of hops than we see in most supplements, or were done with people consuming none alcoholic beer. There are also a lot of animal studies too, although these are of course less useful.
But, it does seem that there's reasonable evidence to suggest hops can help you sleep.
Notable Animal Studies
The most often cited animal study on hopes was on quail, due to them having similar sleep-wake rhythm to humans. The quail were administered different doses of hop extract, similar to the amount found in non-alcoholic beer. The results showed that a dose of 2 mg of hop extract effectively decreased nocturnal activity and preserved the circadian activity/rest rhythm, suggesting a sedative effect on the sleep-wake cycle. 
Clinical Trials of Hops to Help With Sleep
Then we have the human trials, the most commonly referenced of these was conducted on healthy female nurses who worked rotating shifts. The nurses consumed non-alcoholic beer containing hops for 14 days, and their sleep was monitored.  The results showed an improvement in sleep quality, and a shorter time to get to sleep. And on top of that anxiety levels decreased in the group that consumed the non-alcoholic beer, which would make sense as GABA supplementation shows similar results.
There have been a few other studies, including another commonly cited one done on university students which have replicated these findings. 
How Much Hops Should I Take For Sleep?
A lot of supplements for sleep that contain hops tend to dose it around 200mg, although the clinical studies generally shown that 1.5g-2 grams is the effective range.
Hops For Sleep Conclusion
All in all there's some decent evidence to suggest that hops can help you sleep, with a lot of evidence to show that none alcoholic beer can improve sleep and hops as an extract seems to work well too.
1 - https://pubmed.ncbi.nlm.nih.gov/22849837/
2 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399866/
3 - https://pubmed.ncbi.nlm.nih.gov/25183509/