Dictionary+KeyPathSubscript.swift

import Foundation

extension Dictionary {

    subscript(keys: String...) -> Any? {
        var value: Any = self

        for key in keys {
            guard let dictionary = value as? [String: Any] else { return nil }
            guard let newValue = dictionary[key] else { return nil }

            value = newValue
        }

        return value
    }

}

let dict = [
    "foo": [
        "bar": [
            "value": 1
        ]
    ]
]

dict["foo", "bar", "value"] // 1
dict["foo", "bar", "😱"] // nil