diff --git a/core/src/main/kotlin/friend/service/FriendService.kt b/core/src/main/kotlin/friend/service/FriendService.kt
index 9bca006a..f36d5915 100644
--- a/core/src/main/kotlin/friend/service/FriendService.kt
+++ b/core/src/main/kotlin/friend/service/FriendService.kt
@@ -83,7 +83,7 @@ class FriendServiceImpl(
     }
 
     private suspend fun sendFriendRequestPush(fromUser: User, toUserId: String) {
-        val fromUserNickname = userNicknameService.getNicknameDto(fromUser.nickname).nickname
+        val fromUserNickname = userNicknameService.getNicknameDto(fromUser.nickname!!).nickname
         val pushMessage = PushMessage(
             title = "친구 요청",
             body = "'$fromUserNickname'님의 친구 요청을 수락하고 서로의 대표 시간표를 확인해보세요!",
@@ -106,7 +106,7 @@ class FriendServiceImpl(
     }
 
     private suspend fun sendFriendAcceptPush(fromUserId: String, toUser: User) {
-        val toUserNickname = userNicknameService.getNicknameDto(toUser.nickname).nickname
+        val toUserNickname = userNicknameService.getNicknameDto(toUser.nickname!!).nickname
         val pushMessage = PushMessage(
             title = "친구 요청 수락",
             body = "'$toUserNickname'님과 친구가 되었어요.",
diff --git a/core/src/main/kotlin/users/service/UserService.kt b/core/src/main/kotlin/users/service/UserService.kt
index 74c1b07d..89c9d738 100644
--- a/core/src/main/kotlin/users/service/UserService.kt
+++ b/core/src/main/kotlin/users/service/UserService.kt
@@ -57,7 +57,7 @@ class UserServiceImpl(
 
         with(userPatchRequest) {
             nickname?.let {
-                val prevNickname = userNicknameService.getNicknameDto(user.nickname).nickname
+                val prevNickname = userNicknameService.getNicknameDto(user.nickname!!).nickname
                 if (it != prevNickname) {
                     user.nickname = userNicknameService.appendNewTag(it)
                 }