This question is interesting as it suggests that Nora's "wonderful thing" can be understood as a "miracle," which is actually a revealing lens through which we can analyze Nora's desire to be seen, understood and appreciated as a person in her own right.
On one level, Nora's "wonderful thing" describes her hope for a husband who loves her and appreciates her for who she is and not only for her femininity and doll-like appeal. Unfortunately for Nora, this hope is doomed from the start, as evidenced by the title of the play, A Doll's House. Torvald does indeed treat Nora like an empty-headed plaything, and he does not see her for who she is.
When it becomes clear that Torvald does not see Nora in the way that she needs to be seen, she leaves Torvald. Perhaps her following through has actually delivered to Nora her miracle of freedom and independence. By the end of the play, it doesn't matter that Torvald doesn't see her for who she is; Nora got her "wonderful thing" after all, as she now can...
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