Recent attempts to fully resolve the Hubble tension from early dark energy models seem to favor a primordial Harrison-Zeldovich universe with its scalar spectrum being extremely scale invariant. Restoring the Harrison-Zeldovich spectrum within the single-field inflationary paradigm appears to be infeasible, turning to the multifield approach from either curvaton or waterfall models. In this Letter, we successfully align with the Harrison-Zeldovich spectrum within a single-field chaotic inflation by a nonminimal derivative coupling, and the previously disfavored chaotic potential by $\mathrm{Planck}+\mathrm{BICEP}/\mathrm{Keck}$ data in the standard $\mathrm{\Lambda }$-cold-dark-matter model now returns back to the scope of future polarization observations of the cosmic microwave background.

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• Cosmic microwave background
• Cosmology
• Dark energy
• Inflation