Bakken reservoirs hold significant potential for surfactant EOR due to less than 8% primary recovery and billions of barrels of oil left stranded. However, the development and selection of a surfactant-nano package (SNP) is challenging for complex Bakken reservoirs, either as a completion fluid or fracfluid package, or as an EOR agent due to extremely high salinity for an unconventional reservoir (∼30% TDS) with strong presence of di- and tri-valent ions, including Fe, and high temperature ∼150 °C. Various blends of conventional (anionic, nonionic, and amphoteric), bio-based, and bio-surfactants (rhamnolipids and sophorolipids), and nanoparticle blends were examined under Bakken conditions. Formulations were screened for brine and thermal stability, as well as phase stability under Bakken conditions and corresponding changes in interfacial and surface properties were observed. Wettability alterations were assessed by contact angle using core plugs. The dosage of SNP was selected based on economic constraints, and the screening was conducted in three stages. In Stage 1, contact angle measurement, emulsion stability evaluation and interfacial property measurements were performed. In Stage 2, the stability of SNPs in Bakken brine (iron-free) at 150 °C was studied for 7 days. In Stage 3, SNPs were tested in the presence of a high concentration of Fe in brine at 150 °C. Under harsh Bakken conditions (150°C), biosurfactant-nano blend ANA (1 GPT, minimum IFT = 0.370 mN/m) and zwitterionic-nano blend CBDNA (1 GPT, minimum IFT = 0.489 mN/m) effectively reduced interfacial tension without Fe2+. When Fe2+ was introduced alongside 50% citric acid, the CSDNA formulation achieved an ultra-low IFT of 0.045 mN/m, while ANA maintained excellent long-term chemical durability (IFT = 0.21 to 0.29 mN/m over 7 days). A standalone bio-based surfactant P3 similarly exhibited robust stability against precipitation under all conditions. Furthermore, optimal treatments successfully altered shale wettability to a strongly water-wet state, yielding contact angles of 140.7° (ANA), 132.5° (CSDNA), and 151.9° (P3). Finally, demulsion tests confirmed rapid phase separation; the ANA and CBDNA blends reached complete separation (instability index = 0.5) in just 60 and 70 seconds, respectively, effectively preventing stable emulsions. Notably, all tested formulas achieved complete separation in about 5 minutes. This study provides a detailed assessment and screening of various SNPs at economic dosage thresholds for high-temperature and high-salinity Bakken reservoirs with challenging iron content. In unmitigated high-salinity environments, several biosurfactant-nano blends experienced precipitation or interfacial tension instability within a 7 days testing period. However, with the targeted application of 50% citric acid (3 GPT) and WTS (0.05 GPT), the chemical durability of optimal biosurfactant-nanoparticle blends (such as the ANA blend) was significantly enhanced, maintaining consistent, ultra-low IFT values (0.224 to 0.289 mN/m) for 7 days. It is important to note that while the 50% citric acid is valid for preventing iron oxidation and preserving fluid performance, it does not eliminate it entirely. By identifying these optimal, durable combinations, alongside inherently stable standalone options like P3, this research delivers actionable, robust chemical strategies for enhanced oil recovery in complex, iron-rich formations.