Whiskey Creek is a national franchise, they have decent food as such, but it isn't anything you can't find anywhere else. Most all towns in Nebraska of say more than 10,000 pop. will have a local steakhouse, usually located on the main street somewhere. I would assume there is one in Scottsbluff.
Most of these steakhouses, while they may not look like all that much from the outside, are generally fairly nice inside and are considered fine dining by the locals. So don't show up in the evening in jeans and a t-shirt if you don't want to look like a uncouth, out-of-towner, slob. Trust me, I have learned this the hard way more than a few times. One the other hand, attire shouldn't be an issue during lunch.
Also can't go wrong with chicken-fried steak at any local cafe as well.
As for open carry issue, it is local thing. Depends on where you are in Nebraska. Some places it may get you into trouble, especially the further east you go.