A great tool to use if you wish to reset bulk passwords within Active Directory can be downloaded from: Bulk Password Reset Tool
I have tested this and it works apart from the option to change password at next logon, which is something you can do manually by highlighting multiple users, right click, click properties, click the account tab and
click the option to change password at next logon.
Do the same for any other OU’s which include users for whom you have reset passwords. If any accounts are set to ‘password never expires’, the password will not be reset and you will not be able to select the option to change password at next logon.
Please test the tool before applying to a live environment