You must be cautious of which documents you are keeping for yourself and which you are transferring due to laws that protect student data and policies that protect proprietary information (detailed here in the Staff Responsible Use Policy), as you will be liable for any violations of these laws or policies. These are the same requirements that explain why a district employee cannot simply transfer ownership to someone outside of the district, including their own personal Gmail account. That said, you can share and make copies of documents from your NISD account that you wish to keep that do not fall under a protected category.
Right click on the file → Share
Type in the email(s) of the NISD staff member(s) to share the file with editing rights → Send
Right click on the file→ Share
Click on the editor dropdown next to the individual’s name who will be assigned ownership of the file → Share
Once all files have been transferred, you can delete your *Data folder from your Drive