Nesting clips provides you with some benefits. The obvious one is that you declutter your timeline. If you have multiple text boxes for example, what you do is select all the text boxes, right click and select Next clips. To add it to the nested clips, you just have to double click on the nested clips and it will automatically open a tab with all the clips. Another benefit of nesting clips is that you can apply an action to multiple clips in one step. For example, if you've got a clip in three sections, you may want to create a zoom effect or move the window position a few degrees.

Or if you have multiple text boxes as in our case, and you want to fade them you can nest them and add only one fading action