I actually think Shevchenko has a significant striking advantage, but expect her to struggle with Holm's output and pace.
She has a tighter, more technical kicking game on the outside - Holm kicks a lot but she doesn't throw them particularly well. Her teeps are massively telegraphed and she almost always loses her balance and squares herself up when she throws it. Using them a lot against someone with Shevchneko's pedigree might get her countered a lot. Her side kick is good for keeping range, but she needs her opponents to back away from her hands for it to work consistently and Shevchenko is good at holding her ground and countering in the pocket.
I think Shevhchenko's a better boxer too, ironic as that is, at least in close. She has good footwork in the pocket and much better defense/counterpunching in the pocket than Holm. Holm isn't very good in the pocket and relies on her opponents either chasing after her and playing into her stick and move game, or backing away from her hands where she can punt them with kicks as they exit. Shevchenko has the footwork, defense, and composure to walk her down and deny her the opportunities to capitalize on, and counter her when she tries to charge into the pocket.
She also has a technically superior clinch game, but I'm not sure how well that will work for her with Holm's size advantage. Holm looked really good in the clinch against Miesha and Ronda as well.
Skill wise I'd favor Shevchenko. I think she has the tools to exploit a lot of Holm's weaknesses, but I think she'll struggle with Holm because she throws consistently high volume, while Shevchenko is pretty low-output and does a lot of waiting to counter. I think it'll be a close fight and wouldn't be surprised at a split decision. I think it could go either way, but imo the odds definitely warrant a bet on Shevchenko.