When I use Flows to create an item in a different list from another list and it contains a multi-choice column that allows multi-choice, it creates many items based on choices I selected from the original list
The first list "Transportation Request" contains column name "Trucks Type" is choice column checkboxes (allow multi-selection) and the second list contains the same column.
When creating in a first list item and choice multi selection like 3 choices it creates 3 items in the second list based on my selection
Please see the two screenshots
Second List
First List