Your code for the nesting is exactly what Bootstrap recommends: http://getbootstrap.com/css/#grid-nesting
and
https://getbootstrap.com/docs/4.4/layout/grid/#nesting (for Bootstrap 4)
Unless you have a specific need for the show-grid and bs-docs-grid classes, there’s no need to include them. They aren’t part of the base bootstrap CSS.
If you can achieve the layout you need using nested grids, I would certainly use them. They will save you time and reduce potential browser compatibility issues.
Good luck!