Indigenous sovereignty is about having authority over spiritual ways, culture, language, social, political and legal systems, and land. Indigenous sovereignty exists even if it is recognized by nation states such as Canada. It is inherent. It is deeply connected to self-determination and a right to self-government.
An example of an Indigenous community asserting their sovereignty is the Haudenosaunee government creating and issuing their own passports. This act is a statement about how the Haudenosaunee are their own nation, with their own laws and systems. There has been push back to this type of sovereignty, with governments in the United States, Canada, and the United Kingdom refusing to recognize these passports.