Understanding Spatial relationships and sizes
Nesting bowls can lay the foundation to understand sizes. By nesting the bowls your baby would be able to slowly understand the difference between sizes and the spaces they occupy. Over time and experimentation they gain perspective into how smaller objects fit into bigger objects but the vice versa isn't possible. This is nothing but their enhancement of problem solving and critical thinking.
Grasp and release movement
Grasp and release movements are crucial for various developmental aspects. Nesting bowls help your baby explore this. By grasping a bowl and releasing it they are working on Hand-eye coordination which leads to fine motor development. Fine motor development is required to master the usage of tools like pencil, chalks, spoons etc effortlessly.
Numbers and Language skills
Your child can begin counting with the nesting bowls. When an adult sits through the activity the language skills develop exponentially. You can introduce your little one to prepositions( in, over, under etc) and degrees of comparison( small, smallest, big, bigger etc) .
Creativity and exploration
Let the child explore in all ways possible. They can stack the cups, build different shapes or incorporate these bowls in pretend play. For very young children you can introduce two bowls in the beginning and slowly increase the complexity.