I love WeldWerks starriest night but have 0 experience with milk stouts and none brewing with nuts. It’s an 11.5% imperial milk stout with hazelnuts, milk chocolate, and toasted coconut. I am an experienced all grain brewer and would appreciate any help I can get. Thanks! 
All the special ingredients will have to be shaved, ground or whatever to get the flavor out except perhaps the toasted coconut which is already shaved or flaked. I am skeptical that milk chocolate is used. That’s all I got. I hope that helps.
The hazelnuts will be an absolute bollocks unless you can get ones that have already been shelled. No pun intended but they are a tough nut to crack. You might be better off using a hazelnut extract but that can also be problematic (extract or essence? What quantity?). But shelling hundreds of grams of hazelnuts won’t be fun, trust me!
Other than that, this won’t be much different to other stouts you have brewed. You’ll be adding lactose towards the end of the boil, I imagine.
For Rogue’s famous Hazelnut Brown, they use hazelnut extract.
As others mentioned I would go with hazelnut extract with at least a pound of lactose.
From my experience with their beers, there is not doubt in my mind that they are using some type of milk chocolate. I had a WW beer last night that was a milk stout with peanut flour and pureed bananas.
Thanks for the insight. I hear from an insider that I should start with a typical milk stout with plenty of dehusked carafa and dark crystals as well as a large helping of lactose. The really critical part is to use large amounts of toasted coconut as well as hazelnut flour (ideally toasted hazelnuts) in the fermenter shortly after hitting terminal gravity and before crashing. Don’t expect a very good yield on the beer since the coconut and nuts will absorb a lot of beer. I’ll have to look int using nut flour, and no mention of milk chocolate - or chocolate of any kind.
Cheers!