No, it is not. That is the authority of the FEDERAL government. The 11th Amendment in fact prohibits states from suing other states.
Exactly the opposite is true.
Article 3, Section 2, Clause 1
The judicial Power shall extend to all Cases, in Law and Equity, arising under this Constitution, the Laws of the United States, and Treaties made, or which shall be made, under their Authority;—to all Cases affecting Ambassadors, other public Ministers and Consuls;—to all Cases of admiralty and maritime Jurisdiction;—to Controversies to which the United States shall be a Party;—to Controversies between two or more States;—between a State and Citizens of another State; note 10 —between Citizens of different States, —between Citizens of the same State claiming Lands under Grants of different States, and between a State, or the Citizens thereof, and foreign States, Citizens or Subjects.
The next after the bolded portion, between a state and citizens of another state, was removed by Amendment 11.
But the USSC was the proper and legally required venue for Texas to sue the cheating Rodent states who stole the last election, and there is no provision, none at all, for the Supreme Court to summarily decline to hear the case.
Especially not a case the goes to the very heart of what the Constitution exists to protect.