Does "Sacrifice a creature" trigger "sacrifice this creature"
It will not. Sacrificing is a cost paid for the effect to go on stack. Just like you can not spend 1 mana on different costs, you can not spend 1 creature on different costs.

If you wanted it to work the way you described, the ability should be a triggered one, for example it could read: 'When this creature is sacrificed, ...'.

(Also, keep in mind that sacrificing is not targeting anything. Untargettable creatures can still be sacrificed)