In order to meet societal needs for green packaging and improve the barrier performance of paper packaging materials, oxidized cellulose nanofibrils (OCNF) were prepared via oxidization of cellulose nanofibrils (CNF) with sodium periodate. Complex hydrogels were fabricated by compounding OCNF with cationic guar gum (CGG). OCNF/CGG hydrogel was used to coat the base paper. The water vapor barrier and oil resistance properties of the coated paper were evaluated. Inkjet and electrostatic color printers were employed to evaluate the digital printability of the coated paper. Results showed that there was a cross-linking reaction between OCNF and CGG during OCNF/CGG hydrogel fabrication process. When OCNF content was increased in OCNF/CGG hydrogel, the water vapor permeability (WVP) of the coated paper first increased and then decreased at the same coating weight. Experimental data determined that the best water vapor barrier and oil resistance performance was when the ONCF content was 0.4 wt%. The highest oil resistance index value obtained was 12. The oxygen transmission rate (OTR) reached 4.84 cm³/(m² ⋅ 24 h ⋅ atm), which exceeded that of common plastic packaging films such as PET and PA. Furthermore, inkjet printing had a greater color gamut and tone reduction performance for OCNF/CGG hydrogel coated on base paper. The coated paper sized by OCNF/CGG hydrogel met the basic proofing requirements for digital printing has broad application prospects in the field of personalized packaging materials and labels.