Nancy will be different. I don't know how to compare the situations.
Kay Kay works low on the blocks, and her shot can be blocked by someone tall.
Nancy is two inches taller than Brown. I have read that she has developed a sky hook. With the length of her arms, that is probably let go at about nine feet off the floor if she doesn't jump. Can Brown block that? But, mostly, I suspect that they will be used differently.
Vivi may continue to be used like they did Kay Kay and Vivi. I expect Nancy to operate as much at the high post as at the low post, perhaps more. That would force them to bring out a post to guard her. She can hit a shot from the free throw line. She, unlike Vivi and Kay Kay, has learned not to put the ball on the floor (usually). If the ball is always at eight or nine feet in the air, it is difficult to steal or block. I could envision a lot of Nancy at the high post with EJ, Treece, or Maddie taking a smaller defender inside.
I don't think you can work out with weights enough to out-physical a Brown or Mompremier. Your center of gravity is higher than theirs. You will be pushed. Learn to emphasize the fact that you have been pushed and shoot free throws. But, you can reach over them with arms that probably extend about five to six inches above their hands.