The protein from black soldier fly larvae was used as a functional ingredient of a new fiber composite for wound scaffolding. Larvae protein powder (LP) was blended with biodegradable poly(ε-caprolactone) (PCL) and processed in an electrospinning machine using a coaxial feeding/mixing method to produce nanofibers approximately 100–350 nm in diameter. To improve the dispersion and interface bonding of various PCL/LP nanofiber components, a homemade compatibilizer, maleic anhydride-grafted poly(ε-caprolactone) (MPCL), was added to form MPCL/LP nanofibers. The structure, morphology, mechanical properties, water absorption, biocompatibility, wound healing, and biodegradability of PCL/LP and MPCL/LP nanofiber mats were investigated. The results showed enhanced adhesion in the MPCL/LP nanofiber mats compared to PCL/LP nanofiber mats; additionally, the MPCL/LP nanofibers exhibited better tensile strength at break of 0.7–2.2 and a Young's modulus of 9.0–22.8 MPa. Decomposition tests using a simulated body fluid revealed that the addition of LP enhanced the decomposition rate of both PCL/LP and MPCL/LP nanofiber mats and in vitro protein release. Cell proliferation and migration analysis indicated that PCL, MPCL, and their composites were biocompatible for fibroblast (FB) growth. Cell-cycle assays conducted by FBs on PCL/LP and MPCL/LP nanofiber samples showed normal cell growth distribution and biodegradability in a 30-day soil test. When the LP content was 20 wt.%, the degradation rate exceeded 50%. This suggests the potential of these materials as a new scaffold material and as a novel green nanofiber for environmental pollution reduction.