Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue.
• I have read the FAQ and my problem is not listed.

Playground Link

https://typescript-eslint.io/play/#ts=5.7.2&fileType=.ts&esQuery=N4IgZglgNgLgpgJxALhCAvkA&code=JYOwLgpgTgZghgYwgAgEIHsAeyDeAoZZANzgBsBXCALmQGcwpQBzAbjwF888ATCBUuFBQxyIBGGDoQyJhDAAxMqQBGiANYZMACgCUNTWx58BQ5Ain1kveOVJhNNHMjiPky-VmQAfZKOugIbmR2YMNefkEUcxBLazhbeywAeQAHCSkyVzgAfldlXLRPHz8IGACgkPZDAHpq5CEU9CgwWjMmoXFSAE8jGztNADo4AeVkAEIAXmQQW1JkbKtS%2BP6sIZHkGlkFJVUEDSxdGrraAAt0WyCGprBe5cTMVPSQMiHs9cnp2fnFvvvHyWepFe602ckUpBU6k0hy4tToZwuzlItHQ9QgjWatwSmn%2BGSBOXeUxmEO%2BcWxyTSAJew1GoO2EN2%2B20OhYQA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6Y6RAM0WlqYSNkAC1pkA9gEMkyMswDm6KL2jjokcGAC%2BILUA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

interface Box {
  value: string;
}

declare function getFallbackBox(): Box;

declare const defaultBox: { a: { b: Box | undefined } };

declare const defaultBoxOptional: { a?: { b?: Box | undefined } };

// reports correctly
defaultBox.a.b != null ? defaultBox.a.b : getFallbackBox();

// should report
defaultBoxOptional.a?.b != null ? defaultBoxOptional.a?.b : getFallbackBox();

// should also report
defaultBoxOptional.a?.b != null ? defaultBoxOptional.a.b : getFallbackBox();

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/prefer-nullish-coalescing": "error",
  },
};

tsconfig

{
  "compilerOptions": {
    "strictNullChecks": true
  }
}

Expected Result

I expected all cases above to be reported with a suggested fix.

Actual Result

Only the first case (member-expression) is reported.

Additional Info

I think the third case (chain-expression with a member-expression as an alternate) is the more common case, as no-unnecessary-condition will flag the second case (chain-expression).