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The synthesis of polar functionalized cyclic olefin copolymers (COCs) from the coordination copolymerization of norbornene (NB) and polar monomers catalyzed by late transition metal catalysts has been a recent research hotspot. However, few catalysts have achieved efficient copolymerization with commercial vinyl-type polar monomers, such as methyl acrylate (MA). In this contribution, nickel complexes bearing 2-(diarylphosphino)-<i>N</i>-phenylbenzenamine ligands were synthesized and applied as pre-catalysts to catalyze the (co)polymerization of norbornene. Upon the activation of methylaluminoxane (MAO), these nickel catalysts were active for norbornene polymerization with the highest activity achieved being 3.6 × 10⁶ g mol⁻¹ h⁻¹ and the highest number average molecular weight (<i>M</i>_n) of polynorbornene (PNB) reaching 27.4 × 10⁵ g mol⁻¹. Moreover, these nickel catalysts also promoted the copolymerization of norbornene and MA to furnish high-molecular-weight NB/MA copolymers (<i>M</i>_n up to 6.20 × 10⁴ g mol⁻¹) with reasonable MA contents (3.07−5.90 mol%). The molecular weight of PNB and NB/MA copolymers obtained by the present nickel catalysts are remarkably higher than those of the (co)polymers from our previous reported dimethyl substituted phosphinobenzenamine nickel catalyst, suggesting significant progress in this field.