There is a small number of Latin words that can be traced back to Sumerian, e.g. canna “reed”. This was borrowed from Sumerian to Akkadian, then from Akkadian to West Semitic, then from Semitic to Greek, then from Greek to Latin, and from Latin to English “cane” and others. Each of these steps is well documented in known languages. But in the case of Sumerian itu and Latin idus there are no such links. This makes any connection between them highly unlikely.
Idus does not have a recognised Indo-European etymology. The concept of a “Nostratic” super-language is not mainstream linguistic doctrine. In any event, the adherents of “Nostratic” do not normally count Sumerian or Basque as members of that complex.