ModeWithNonce no longer exists.
diff --git a/cryptography/bindings/openssl/api.py b/cryptography/bindings/openssl/api.py
index af7fe43..917c184 100644
--- a/cryptography/bindings/openssl/api.py
+++ b/cryptography/bindings/openssl/api.py
@@ -76,8 +76,6 @@
         assert evp_cipher != self._ffi.NULL
         if isinstance(mode, interfaces.ModeWithInitializationVector):
             iv_nonce = mode.initialization_vector
-        elif isinstance(mode, interfaces.ModeWithNonce):
-            iv_nonce = mode.nonce
         else:
             iv_nonce = self._ffi.NULL