From the Dhammasangani
katame dhammā upādāniyā? tīsu bhūmīsu kusalaṃ, akusalaṃ, tīsu bhūmīsu vipāko, tīsu bhūmīsu kiriyābyākataṃ, sabbañca rūpaṃ – ime dhammā upādāniyā.
katame dhammā anupādāniyā? cattāro maggā apariyāpannā, cattāri ca sāmaññaphalāni, nibbānañca – ime dhammā anupādāniyā.
Since Nibbana has no diversity in terms of past, present future etc, it does not come under khandha analysis. But is counted as an ayatana(dhammayatana) and dhatu(dhammadhatu).