I'm somewhat new, but I've been experimenting with a kind of hybrid consume deck with Nithral - I've climbed from around 2600 MMR to 3600 MMR in the past 2-3 days or so though so it's been working pretty well. Will see how far it takes me.
http://www.gwentdb.com/deckbuilder/...:2:3;50091:2:2;50195:2:1;50198:4:1;50199:4:1;
I really like Nithral because scorch is about the only thing that removes him immediately when you play him on turn 1, so you'll almost always get a lot of value out of Nithral since it's exceedingly rare to not draw at least 1 wild hunt rider or king of beggars (KoB isn't truly necessary, but I like having him largely because it lets me mulligan away my wild hunt riders freely, and if for whatever reason I don't play wild hunt riders round 1 I don't get screwed over by drawing into 1 of them if I mulliganed them away too).
Regis might seem a bit random - more or less he virtually always gets played round 2 to make round 3 easier instead of trying for card advantage. I considered Avallach, but ultimately I don't think this deck values card advantage highly enough to want to use him (I figure getting 10 extra power on the board for round 3 is about as good as being a card up on the opponent anyway in most matchups, or at least the difference isn't so big to be worth the 14 power difference in round 2). You need to be a bit careful with the Katakan and Regis if you have Caranthir in hand, but you can usually find an opportunity to play them in different rounds or worst case scenario consume them before playing Caranthir. I don't have a very big collection though so I haven't had a lot of freedom to experiment with different card choices still.