Hi Ashley

Thank you for reaching out! While there isn't a keyboard shortcut to add chairs one option would be to manually add the table and chairs once and then group the selection to copy and paste. The steps would look like this.

1. Create the round table

2. Add the chairs 

3. Group the selection (Ctrl + G)

4. Copy and Paste (Ctrl + C Ctrl + V)

You can then alternate the size of these tables and chairs together by modifying the sizing option near the corner of the object. 

Please let me know if you have any other questions!

This is not helpful. How do I add chairs to a round table so they are perfectly aligned and evenly spaced out without manually adding one chair at a time?

Hi Kristen! Thanks for commenting in the community. Unfortunately there isn't a feature that allows you to do what you are asking. The best approach would be to go through the process above and then copy/paste as many of them as you need. If in the future you would like to see a feature that lets you perfectly align chairs you can fill out this feature request form to bring the idea to the attention of our product team. I apologize for any inconvenience this causes to your diagramming experience and thanks again for reaching out. Feedback from our users is how we continuously improve Lucidchart!