Strong \({\mathcal {H}}\) -tensors play a significant role in identifying the positive definiteness of homogeneous polynomials. Motivated by the definition of \(\mathcal {N}\) -scal matrices, this paper first introduces two new subclasses of strong \({\mathcal {H}}\) -tensors, namely \({{\mathcal {N}}}\) -scal tensors and strong \({{\mathcal {N}}}\) -scal tensors. Second, it analyzes the relationships among \({{\mathcal {N}}}\) -scal tensors, strong \({{\mathcal {N}}}\) -scal tensors, and Nekrasov tensors. Finally, as applications, two new methods are proposed to determine the positive definiteness of even-order real symmetric tensors based on \({{\mathcal {N}}}\) -scal tensors and strong \({{\mathcal {N}}}\) -scal tensors, with numerical examples provided to illustrate the results.