MS-SQL is a relational database. Oracle is a database with an SQL-like command language. There is a significant difference, neither one is inherantly better or worse than the other. They aren't comparable.
No relational database can have anything like Oracle's nested tables. Nested tables implicitly violate the first normal form.
In a relational database like MS-SQL, you can do exactly the same thing as a nested table by using a foreign key relationship. Create a second table using the same schema you would use for an Oracle nested table, adding a "link" column. Include the value from the "link" column in the parent row, so that you can join the main table to the logically "nested" table.