Add a scale layout of the whole suite space including the nook with dimensions. For this nook include wall heights.

Can you elaborate

We need to see your plan and also pics of the whole space . The plan done on graph paper showing every part of the plan every measurement clearly marked , posted here in jpeg format in a comment DO NOT start another post.

Take measurements of your spaces and draw the space on graph paper using the squares as 1 equals 6" or whatever fits the size of your sheet of paper. Or use a program.

7 Best Floor Plan Software for Drawing Floor Plans (Free + Paid) This necessary to get ideas on how to integrate the space in your bathroom reno. And maybe come up with other ideas.

Pat. Stop that command language in all your posts.

Search Houzz for under staircase utilization ideas. Great space for roll out cabinet drawers, or if enough height a makeup table.

Be cause it is so deep, a closet will be inconvenient. Consider custom drawers that fill the space and can be accessed more easily than ducking into a closet.

I like this suggestion from Maureen:

what are your storage needs? Consider those first. And remember, you don’t have to use the entire depth of that space. If you really only need to store extra toilet paper and soap and knee braces, just build what will accommodate that and close off the back.

I had a long row of closets that I converted into a more compact coat closet, a laundry, and a storage space. My contractors invented this pull-out for me, which stores all our sports gear and related stuff. If your space is taller, you could put shelves in there too.

this is the laundry, heh

Can you share pics of the area for the bathroom as well.

One of the very few appropriate applications of a barn door inside a house:

I have barn doors on a 6' opening to a space under my stairs it allow me to open only a bit or the whole 6' the spsce has our wine making stuff and works great . In this case I need more info . We need to know what it is you want to store. The plan is done on graph paper to scale of the whole space including the bathroom every meausrement clearly marked all windows and doorways and ehere those lead and for sur einclude this space Then you post that here in jpeg format in a comment. DO NOT start another post, all things relating to this post are now dealt with in comments.

And another one disappears

I would do under stairs drawers for additional storage. Something like these:

Michigan Summer Home · More Info

Lakeside Classic · More Info

Here's another cute idea for a pet bed with pullout bowls:

Decorator's Showcase House, San Francisco - 2015 · More Info