Hey there @drewjohnson71! So under the Unreal Engine Quixel license, as long as it’s use falls within UE’s content EULA, you are good commercially. So the short answer is yes as long as you aren’t using them outside of Unreal. The long answer would be to make sure everything is good with the content EULA.
Unlimited Megascans access for Unreal Engine based products: Just sign in with your Epic Games account to get unlimited access to the Megascans library. This Megascans access is licensed for use with Unreal Engine only and treats Megascans assets as UE-Only Content under the Epic Games Content License Agreement.
Quote taken from here