Hello everyone:
Now this is possible with a plugin:
https://github.com/littlebusters/Adjust-size-by-shortcut-for-AdobeXD
You can search for the name in XD's plugin manager

and if you on a Mac, you can map the shortcuts using this notation
Plugins->Adjust Size by Shortcut->Command Name
I did them as in other software and its working great.
Plugins->Adjust Size by Shortcut->Shrink Width

In Sketch / Studio it is possible to change a layer's size using the keyboard only: cmd + right arrow for example increases the object's width by one pixel. This is especially useful if you need to be extra precise. When doing so with the mouse (or a graphic-tablet) you always have to zoom in quite a lot to guarantee that your mouse movement only equals one pixel.

Additionally holding down the shift modifier key would increase the increment to 10 px

This is like the plugin Nudge.it we use to Sketch

This is the same feature request: https://adobexd.uservoice.com/forums/353007-adobe-xd-feature-requests/suggestions/13045278-custom-multiple-nudge-distances

Really surprises me this has still not been implemented. I tried XD when it released, and couldn't get used to not having this feature. I just came back to try it for the 2nd time after the new feature releases, and was in shock realizing you still could not do this with keyboard shortcuts. I even found my initial comment in this thread from 2 years ago.

increase and decrease size!

Pleeeeaase

Pleeease, make this happen!

Change Object Size
Cmd + Arrows

Change Units by 8 pixels
Shift + Cmd + Arrows

Pleeeease, i have a company with 24 designers and we need this to migrate from Sketch to Adobe XD

I cant switch until this is implemented, seriously the most used feature in my design process.

Pleease, make it pleeease! I need these!

Is it possible to add a shortcut manually now?

YES PLEASE!

cmd+shift+arrow
ctrl+shift+arrow

Sketch and Figma have a convenient shortcut for changing layer dimensions by using ctrl/cmd+shift+arrow to change width and height of shapes, text boxes and other elements.

I wish to have it in adobe XD

I've used Photoshop for almost 10 years doing UI design. This feature, although small, was a large part of what pulled me over to Sketch. Please add this feature as its a massive time saver. It can be used on anything in sketch. Text areas, shapes, circles, symbols, etc...

The small and simple changes make the biggest difference.

I can't believe this is not done yet.. Makes me totally unproductive in XD compared to Sketch :(

YES! I'm waiting for this feature for almost two years now. Come on, guys! It's not that difficult, and all competitors do it.

Yes Yes Yes!

Please, what makes me want to never fully move into xd today is the lack of this (and similar) features that are just SO tedious to do in any other way than the keyboard.

P.S. don listen to George. Cmd-up should ofc decrease height and down increase.

This is a huge time saver for me in sketch. I heartily agree with the need for Nudge.it functionality as well. If you've set a base multiplier for your design (we use 8px) it save a ton of time when iterating to be able to move things in set increments.

We're in the process of assessing XD to see if it's a viable alternative to Sketch and this is honestly a feature that has me leaning towards Sketch.