This script will work to read a text file and create an Excel table with all the items that are separated by commas in their own row, first column:
set a to choose file --Select your .txt file you want processed
set aa to open for access a
set b to read aa --This will read everything in the chosen file
close access aa
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to ","
set c to b's every text item --This creates a list of all the text that is separated by commas
set AppleScript's text item delimiters to astid
tell application "Microsoft Excel"
activate
repeat with cc from 1 to (c's length)
set value of cell 1 of row cc to (item cc of c) --This will create a new row for each item, and place that item in the first cell
end repeat
end tell
Try it out on a few files to make sure it works, then we can help you to get it to process as many files as you need, creating separate worksheets for each.