Section Constants says:

Constants

You can use constant values in the following ranges:

• For nint: Int32.MinValue to Int32.MaxValue.
• For nuint: UInt32.MinValue to UInt32.MaxValue.

This is only correct for 32-bit processes.
As nint and nuint are native sized, so on 64-bit processes the range for nint is Int64.MinValue to Int64.MaxValue.
Or generalized: the range is the same as for IntPtr, so [IntPtr.MinSize, IntPtr.MaxSize]

Document Details

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• ID: 71aa383e-70a4-855c-e639-c06c479f918e
• Version Independent ID: 7c19d234-b117-196d-d1a9-d29be9de5ff2
• Content: nint and nuint types - C# reference
• Content Source: docs/csharp/language-reference/builtin-types/nint-nuint.md
• Product: dotnet-csharp
• Technology: csharp-language-reference
• GitHub Login: @BillWagner
• Microsoft Alias: wiwagn