From the service manual for a 2008 Nissan Sentra with mr20de: spark plug torque is 19.6 Nm, 2.0 kg-m, 14 lb-ft, so 23 Nm is too much, you could damage the cylinder head.
Information is not much.. It is the marine version of the Nissan SD22. Internally it is the same engine, but the manifolds are different and marine version has a direct coupled mechanical governor.