SQL Server has actually had NoSQL data storage and analysis products bundled with it for over a decade. Take for example, Analysis Services. People don't generally think about OLAP products being a NoSQL database engine, but they actually are. Also, Full-Text Search, FileStream, and Common Language Runtime services can maintain huge unstructured data stored external to the relational (mdf, ndf) data files, but are tightly integrated with the RDMS engine and T-SQL language.

If your database is storing huge unstructured chunks of junk in varchar columns, then SQL Server itself has other services bundled with it that can offer a better solutuon, without resorting to a 3rd party product.