Hel-Raider scouts are essentially just undead Raider Scouts, and so the same tactics apply.
Raider Scouts make use of a sling to hurl projectiles at Kratos. They're pests, but once you get in close, they don't have much to offer. Avoid their fire, and then let loose with a barehanded combo to stun them into submission. Their stun bar fills very quickly, so this shouldn't be much of a problem.
The only thing to watch out for is a Scout's melee attack, in which they swing their sling in a desperate fashion. It's a slow attack that can be easily dodged, but if it does hit, it gives them an opportunity to run away.
How many Hel-Raider Scouts have you smashed into submission? Be sure to check out our full God of War Ragnarok guide for information on how to beat every enemy, and much more.