Upon closer inspection, I don't think that's from a Betty although that is a really good guess. The Betty had a frame that wrapped all the way around between the plexiglass nose piece and where it attached to the fuselage (see image below). The nose cone in the original post only has a partial frame that only goes maybe half way around the nose cone. At the bottom of the photo this is also a smaller round section of structure. Whatever was there is missing (gun port? landing light?). From what I can tell, the Betty did not have that unless it was specific to a variant. I agree with cvairwerks, it is definitely not from a B-29.