Almond butter tastes like almonds.
If you like almonds, you'll like it. Cashew butter is a bit milder (I prefer almond butter, I like the stronger taste.).
I love nutella...Only thing about nutella is that there is a ton of sugar and saturated fat. Not necessarily horrible for you, but I would definitely steer more towards the natural nut butters that are primarily nuts and not a bunch of added sugars and oils and salt.
I LOVE nuts and seeds of all kinds, mmmmmm...perfect snack.
ETA: There IS a natural hazelnut butter...I haven't tried it, but I want to. If its the chocolate hazelnut flavor you want, it might be better to buy some hazelnut butter without all the added junk and just make your own chocolate version with it.