I can't speak to using maple syrup in a beer since I've never done it. But as for getting this kind of beer, I'd be sure to mash a little higher than my normal beers, say around 155F. Also, I'm a fan of adding the sugar, molasses in this case, directly to the primary towards the end of the high krausen phase and gently stirring it in to dissolve it. I think this lets the yeast work more completely by not getting lazy eating a bunch of simple sugar at the start of fermentation. Lastly, if you're looking for a more nutty flavor, I'd suggest looking into using Marris Otter malt instead of normal pale 2-row.