Rodeo Queen sunglasses - Michele Simms - A Christmas Karen
Rodeo Queen sunglasses all have studded rhinestones pattern on the front of the glasses, but come in a variety of metal temple designs, ranging from a crown, a horse, horse shoe, a cross
Based on the first images we have from the movie, it looks like Michele Simms as Karen wears the "Belle" model, as pictured on the left, but you can find a range of other, similar designs on Amazon.
Buy the Rodeo Queen Belle on Amazon for $20.
Reference: Rodeo Queen Belle