This study explores the efficacy of electrospun polyvinyl alcohol (PVA) nanofibers loaded with C.I. Disperse Red 60 (DR60) as dyeing agents for polyethylene terephthalate (PET) fabrics in a supercritical carbon dioxide environment. The fabrication of DR60-loaded PVA nanofibers (DR60/NF-1) involved a spinning solution containing water and dimethyl sulfoxide. Analysis revealed that PET fabrics treated with DR60/NF-1 exhibited significantly higher K/S values (8.51) compared to those treated with DR60 powder (3.19), resulting in visibly distinct coloration among dyed fabrics (ΔEab: 17.77). Additionally, DR60/NF-1 demonstrated superior dye uptake by PET fabrics (15.07 mg/g) at a dosage of 3% (o.w.f.) compared to DR60 powder (13.19 mg/g) at a dosage of 4% (o.w.f.). These findings underscore the potential of DR60-loaded PVA nanofibers to enhance coloration and dye uptake in PET fabric dyeing processes conducted under supercritical carbon dioxide conditions, offering promising avenues for advancing efficiency and sustainability in textile manufacturing.