ScrollViewを持ったAlertDialogを表示する ref: https://qiita.com/masaibar/items/33ac44545c0d37caee50

MainActivity.kt

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    AlertDialog.Builder(applicationContext)
        .setTitle("title")
        .setView(R.layout.view_scrollable_text)
        .setPositiveButton(
            "OK"
        ) { _, _ ->
            // Do nothing
        }
        .show()
}

view_scrollable_text.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="hoge" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="fuga" />
    </LinearLayout>
</ScrollView>